Warning light remains ON.

a. Oil pressure switch failure

    Cracked diaphragm or oil leakage within switch

Replace.

    Broken spring or seized contacts

Replace.

b. Low oil pressure

    Clogging of oil filter

Replace.

    Malfunction of oil by-pass valve in oil filter

Replace.

    Malfunction of oil relief valve in oil pump

Clean or replace.

    Clogged oil passage

Clean.

    Excessive tip clearance and side clearance of oil pump rotor

Replace.

    Clogged oil strainer or broken pipe

Clean or replace.

c. No oil pressure

    Insufficient engine oil (degradation, etc.)

Replace.

    Broken pipe of oil strainer

Replace.

    Stuck oil pump rotor

Replace.

Warning light does not illuminate.

a. Defective combination meter

Replace.

b. Poor contact of switch contact points

Replace.

c. Disconnection of wiring

Repair.

Warning light flickers momentarily.

a. Defective terminal contact

Repair.

b. Defective wiring harness

Repair.

c. Low oil pressure

Check for the same possible causes from list “Warning light remains ON” — b.